Antielectrostatic agents are used in a number of contexts and in conjunction with a wide variety of materials. Depending on the use, it may be necessary to provide antielectrostatic agents which are thermally stable, stable to chemicals with which the agents come into contact, and which may be incorporated into existent materials or structures without deterioration of mechanical properties. In addition, in the preparation of conductive composite materials, compatibility and processability of the antielectrostatic agent with the base material is required as well.
One important area in which antielectrostatic agents are needed--and the context from which the present invention derives--is in the interior of fuel lines and other fuel system parts. Typically, the plastics which are used as the interior coatings are selected such that corrosion and degradation resistance are provided, as is chemical resistance and flexural toughness. Nylon 12 is one such material which has been found to be particularly advantageous in this regard. However, a serious problem which has arisen with Nylon 12 is the buildup of electrostatic charge during use. This is obviously an undesirable and potentially very dangerous problem.
One approach to eliminate electrostatic discharge in Nylon 12 has been the incorporation of carbon black to render the plastic more conductive. However, the incorporation of carbon black was found to lead to a loss of needed mechanical properties such as flexibility and elongation due to very high loading required to achieve conductivity.
A second approach to eliminate electrostatic discharge in plastics is set forth in European Patent Publication Nos. 283,985 and 287,092. Briefly, this method involves the use of polyether-based polymers and blends thereof with thermoplastic materials such as polystyrene, styrene copolymers, polyvinyl chloride, and polypropylene to provide electrostatic discharge protection. However, these materials are not suitable for use with Nylon 12 because of its hydrophobicity and the need for high processing temperatures.
The present invention addresses the aforementioned issues insofar as antielectrostatic agents are now provided which are thermally stable and compatible with hydrophobic materials such as Nylon 12. The novel antielectrostatic agents have been found to provide a number of additional advantages as well. Primarily, they are readily processable with Nylon 12 or other polymeric materials, even at temperatures of 150.degree. C. to 250.degree. C., or higher. The antielectrostatic agents of the invention are resistant to swelling in organic fluids such as gasoline and are useful in preparing composite materials which have superior mechanical properties, i.e., the materials will not tend to crack or otherwise rupture at high temperatures or when subjected to routine stress.